*
  margin: 0
  padding: 0

html, body, #app
  width: 100%
  height: 100%


#app 
  display: flex
  flex-direction: column
  header, footer
    height: 46px
    display: flex
    justify-content: space-around
    align-content: center
    background: skyblue
  main 
    flex: 1
    overflow-y: scroll
    height: 100%